<!-- 开发环境版本，包含了有帮助的命令行警告 -->
<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>

<div id="aa">
	<form v-on:submit.prevent="addNewTodo">
		<label for="new-todo">Add a todo</label>
		<input 
			v-model="newTodoText" 
			id="new-todo" 
			placeholder="E.g. Feed the cat" />
		<button>Add</button>
	</form>
	<ul>
		<li
			is="todo-item"
			v-for="(todo, index) in todos"
			v-bind:key="todo.id"
			v-bind:title="todo.title"
			v-on:remove="todos.splice(index, 1)"/>
	</ul>
</div>

<script>
<!--
定义组件
点击“Remove”按钮时，触发当前实例上的事件，即v-on:remove事件
-->
Vue.component('todo-item', {
	template: '\
	    <li>\
		{{ title }}\
		<button v-on:click="$emit(\'remove\')">Remove</button>\
		</li>\
	',
	props: ['title']
})

  
//数据对象
var data = {
	newTodoText: '',
	todos: [
		{id: 1, title: 'Do the dishes'},
		{id: 2, title: 'Take out the trash'},
		{id: 3, title: 'Mow the lawn'}
	],
	nextTodoId: 4
}

//实例
var vm = new Vue({
	el: '#aa',
	data: data,
	methods: {
		addNewTodo: function() {
			this.todos.push({
				id: this.nextTodoId++,
				title: this.newTodoText
			})
			this.newTodoText = ''
		}
	}
})
</script>